The general concept of suspending objects from a ceiling by using a cord looped over a pulley is well known. Likewise, the general concept of a locking pulley which may selectively restrict movement of a cord in one direction is well known.
U.S. Pat. No. 2,702,176, issued Feb. 15, 1955, to William J. Dulle discloses a pulley assembly attached to a ceiling-mounted track for raising, lowering and suspending articles therefrom. Links of a chain are engaged in a keyhole-shaped notch to secure articles in a suspended positon. U.S. Pat. No. 3,944,186, issued Mar. 16, 1976, to Ruediger Einhorn et al. discloses a ceiling-mounted locking pulley assembly for suspending plants or other articles overhead. It shows a pulley wheel having a circumferential groove and one or more locking grooves. Each locking groove is helically formed on the pulley wheel extending from the circumferential groove to one side thereof and gradually diminishing in depth as the distance from the groove increases U.S. Pat. No. 4,187,996, issued Feb. 12, 1980, to Sol Ehrlich, discloses a spring-wound spool apparatus for suspending potted plants or similar articles overhead for a ceiling. Each of these patents should be carefully considered for the purpose of putting the present invention into proper perspective relative to the prior art.